Subp. 3.

Negative pressure required.

Subp. 4.

Calculation of time needed after a release.

Before receiving, using, or storing a radioactive gas, the licensee must calculate the amount of time needed after a release to reduce the concentration in the area of use to the occupational limit listed in part 4731.2750. The calculation must be based on the highest activity of gas handled in a single container and the measured available air exhaust rate.

Subp. 5.

Posting time needed after a release.

A licensee must post the time needed after a release to reduce the concentration to the occupational limit calculated for the area of use and require that, in case of a gas spill, individuals evacuate the room until the posted time has elapsed.